We are studying murine intracisternal Type-A particles as a model for the expression of integrated viral genes. BIBLIOGRAPHIC REFERENCES: Kuff, E.L., Lueders, K.K., Orenstein, J.M., and Wilson, S.H.: Differential response of type C and intracisternal type A particle markers in cells treated with iododeoxyuridine and dexamethasone. J. Virology 19: 709-716, 1976. Lueders, K.K., Segal, S., and Kuff, E.L.: RNA sequences specifically associated with mouse intracisternal A-particles. Cell 11: 815-826, 1977.